Torsionally vibrating viscosity and density sensor for downhole applications

ABSTRACT

An apparatus and method for estimating a parameter of interest in a downhole fluid using a fluid analyzer. The fluid analyzer may include: a member configured to vibrate in response to an energy source, a housing to enclose the member and receive a fluid, and a sensor configured to respond to shear waves induced in the fluid by the vibration of the member. The member may be formed at least in part of a material responsive to a magnetic field or a piezoelectric material. Also disclosed is a method of use for the apparatus.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Patent Application Ser. No. 61/390,867, filed on 7 Oct. 2010 the disclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

This disclosure generally relates to acquiring, analyzing, and/or retrieving fluid samples. In certain aspects, the disclosure relates to analysis of fluids in a borehole penetrating an earth formation.

BACKGROUND OF THE DISCLOSURE

Fluid evaluation techniques are well known. Broadly speaking, analysis of fluids may provide valuable data indicative of formation and wellbore parameters. Many fluids, such as formation fluids, production fluids, and drilling fluids, contain a large number of components with a complex composition.

The complex composition of such fluids may be sensitive to changes in the environment, e.g., pressure changes, temperature changes, contamination, etc. Thus, retrieval of a sample may cause unwanted separation or precipitation within the fluid. Additionally, some components of the fluid may change state (gas to liquid, or liquid to solid) when removed to surface conditions. If precipitation or separation occurs, it may not be possible to restore the original composition of the fluid.

This disclosure provides an apparatus and method to more effectively retrieve and analyze fluids.

SUMMARY OF THE DISCLOSURE

In aspects, this disclosure generally relates to exploration for hydrocarbons involving in situ analysis of fluids in a borehole penetrating an earth formation. More specifically, this disclosure relates to analysis of fluids using a device formed with a vibrating member.

One embodiment according to the present disclosure includes an apparatus for estimating at least one parameter of interest relating to a fluid, comprising: a member in the fluid, the member being responsive to an applied energy field, wherein the response includes at least one mode of vibration.

Another embodiment according to the present invention may include a method for estimating at least one parameter of interest relating to a fluid, comprising: estimating the at least one parameter of interest using information representative of a damping of at least one mode of vibration of a member in the fluid, the motion being caused by an applied energy field.

Examples of the certain features of the disclosure have been summarized rather broadly in order that the detailed description thereof that follows may be better understood and in order that the contributions they represent to the art may be appreciated.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed understanding of the present disclosure, reference should be made to the following detailed description of the embodiments, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals, wherein:

FIG. 1 shows a schematic of a fluid analyzer deployed in a wellbore along a wireline according to one embodiment of the present disclosure;

FIG. 2 shows a schematic of a fluid analyzer according to one embodiment of the present disclosure;

FIG. 3 shows a schematic of a fluid analyzer according to another embodiment of the present disclosure;

FIG. 4 shows a schematic of a fluid analyzer according to another embodiment of the present disclosure;

FIG. 5 shows a schematic of a fluid analyzer according to another embodiment of the present disclosure;

FIG. 6 shows a schematic of a fluid analyzer according to another embodiment of the present disclosure;

FIG. 7 shows a flow chart of a method for estimating a parameter of interest using a fluid analyzer according to one embodiment of the present disclosure; and

FIG. 8 shows a flow chart of another method for estimating a parameter of interest using a fluid analyzer according to one embodiment of the present disclosure.

DETAILED DESCRIPTION

This disclosure generally relates to analysis of fluids. In one aspect, the present disclosure relates to the analysis of fluids using an analyzer that includes a member configured to be immersed in a fluid and to vibrate in the fluid, causing shear waves. The vibratory motion or response of the member may be induced by exposing the member to an applied energy field. In some embodiments, the applied energy field may be generated by an energy source, such as a cycled or pulsed electromagnetic source (e.g., electromagnet, AC, or pulsed DC). In some embodiments, the applied energy field may include a magnetic field. The member may be formed of a material that is responsive to the pulsed electromagnetic source or a piezoelectric material. In some embodiments, the member may be isolated from other sources of vibrations or energy. When the energy source is active, motion may be induced in the member; however, when energy source is inactive, the induced motion and shear waves in the fluid may be damped by the presence of fluid surrounding the member. The member may be disposed within a housing or container such that the primary damping of the motion of the member may be due to the presence of the surrounding fluid. The damping or decay of the shear waves may be measured using a sensor configured generate information indicative of an estimate of at least one of: (i) the response of the member, (ii) a magnetic field generated by the response of the member, (iii) an amount of energy consumed by the source of the applied energy field, and (iv) a force on the member. Herein, “information” may include raw data, processed data, analog signals, and digital signals. Characteristics of the decay may be used to estimate the density viscosity product of the fluid. In some embodiments, the member may be moved or vibrated in different modes, such as torsionally and laterally, allowing viscosity and density to be estimated even if other properties of the fluid (e.g. compressivity) are unknown. In some embodiments, the impedance of a piezoelectric member may be measured, as the impedance may be indicative of the shear wave decay due to the fluid. Viscosity and density may be used to estimate gas/oil ratio, estimate the quality of the fluid sample taken from formation, estimate a contamination level, and calculate permeability of the formation.

Referring initially to FIG. 1, there is schematically represented a cross-section of a subterranean formation 10 in which is drilled a borehole 12. Suspended within the borehole 12 at the bottom end of a conveyance device such as a wireline 14 is a downhole assembly 100. The wireline 14 is often carried over a pulley 18 supported by a derrick 20. Wireline deployment and retrieval is performed by a powered winch carried by a service truck 22, for example. A control panel 24 interconnected to the downhole assembly 100 through the wireline 14 by conventional means controls transmission of electrical power, data/command signals, and also provides control over operation of the components in the downhole assembly 100. The data may be transmitted in analog or digital form. Downhole assembly 100 may include a fluid testing module 112. Downhole assembly 100 may also include a sampling device 110. Herein, the downhole assembly 100 may be used in a drilling system (not shown) as well as a wireline. While a wireline conveyance system has been shown, it should be understood that embodiments of the present disclosure may be utilized in connection with tools conveyed via rigid carriers (e.g., jointed tubular or coiled tubing) as well as non-rigid carriers (e.g., wireline, slickline, e-line, etc.). Some embodiments of the present disclosure may be deployed along with Logging While Drilling/Measurement While Drilling (LWD/MWD) tools.

FIG. 2 shows an exemplary embodiment according to the present disclosure. The fluid analyzer 200 may be formed from a housing 210, such as a tubular or pipe, configured to receive a fluid 220. Fluid 220 may include, but is not limited to, one or more of: (i) drilling fluid, (ii) formation fluid, and (iii) fracturing fluid. Fluid 220 may enter the housing 210 through inlet 224 (upstream) and exit through outlet 228 (downstream). In some embodiments, the inlet 224 and outlet 228 may be reversible. A member 230 may be mounted or operably connected to the inside of the housing 210. The member 230 may include a flexure arm 240 and a head 250, which may be distinct parts or sections of a uniform member. The member 230 may be located within housing 210 such that it is surrounded by fluid 220. A magnetic field source 260 may be located outside the housing 210 and positioned in proximity to the head 250 portion of the member 230. The magnetic field source 260 may include an electromagnet. The head 250 may include a magnet 270 responsive to the magnetic field generated by the magnetic field source 260. The use of a magnetic field source for applying a magnetic field to the member is exemplary and illustrative only, as other types of energy sources may be used to apply an energy field to the member. The magnet 270 may include at least one of: (i) an electromagnet and (ii) a permanent magnet. The use of a magnet is exemplary and illustrative only, as any element, powered or unpowered, that is responsive to a magnetic field. A sensor 280 may be configured to measure changes in a magnetic field may be disposed near the head 250. Using a sensor 280 configured to response to magnetic field changes is exemplary and illustrative only, as some embodiments may use sensors configured to respond to other stimuli, including, but not limited to, one or more of: (i) mechanical force, (ii) electric fields, (iii) electromagnetic radiation, (iv) differential heating, and (v) electrostatic force. In some embodiments, the sensor 280 may be radially collocated with the magnet 270, however, the sensor 280 may be located inside or outside of housing 210 and may be located ahead of, alongside, or behind the head 250. In operation, the magnetic field source 260 may be pulsed to induce vibrations in the member 230 when the magnet 270 in the head 250 responds to the generated magnetic field. The force induced on the head 250 by the magnetic field may cause the member 230 to rotate or move in at least one mode of vibration, such as torsionally and/or laterally. The motion of the member 230 may generate a shear wave in the fluid 220. The rate of damping of the shear wave in the fluid 220 may be used to characterize properties of the fluid 220. The damping of the shear wave may be estimated from the change in motion of the member 230 as the fluid 220 resists the vibratory motion of the member 230. The change in motion of the member 230 may be estimated from the alteration of the magnetic field generated by the motion of magnet 270. The motion of the magnet 270 may generate a magnetic field that may be detected by sensor 280. The amount and/or rate of change in the magnetic field, in terms of phase and amplitude, may be used to determine rheological properties of the fluid 220. In some embodiments, at least part of the magnetic field source 260 may be used as the sensor by configuring the magnetic field source 260 to provide a signal responsive to the magnetic field from magnet 270 when the magnetic field source 260 is not generating a magnetic field. In the case of a dual function magnetic field source 260, sensor 280 may not be necessary. In some embodiments, a catcher 290 may be positioned upstream of the head 250 to reduce the amount of magnetic particles in fluid 220 prior to the analysis processes. The catcher 290 may include at least one of: (i) an electromagnet and (ii) a permanent magnet. The catcher 290 may have a container to collect the magnetic particles.

FIG. 3 shows another embodiment according to the present disclosure, where analyzer 300 uses a sensor 380 operably coupled to the flexure arm 240. The motion of the member 230 may be estimated by the stress detected at the sensor 380. From this stress, the rheological properties of fluid 220 may be estimated. The sensor 380 can also be a vibration sensitive device coupled through the wall of the enclosure.

FIG. 4 shows another embodiment according to the present disclosure, where analyzer 400 does not use a magnet in head 250. Instead, head 250 may include a metallic layer 450 or comprise one or more metals that are responsive to a magnetic field. Head 250 may include indentions (such as eyelets or slots) 410 that include walls 420 that are substantially perpendicular to the magnetic field produced by magnetic field source 260. In operation, the magnetic field generated by the magnetic field source 260 may be cycled and interact with the metal in the layer 450. The interaction may result in vibrations that cause shear waves in the fluid 220. The damping of these vibrations may be detected by sensor 380.

FIG. 5 shows an exemplary embodiment where analyzer 500 includes a housing 510 such as a tubular or pipe, configured to receive a fluid 220. Fluid 220 may enter the housing 510 through inlet 524 (upstream) and exit through outlet 528 (downstream). In some embodiments, the inlet 524 and outlet 528 may be reversible. A piezoelectric member 530 may be mounted or operably connected to the inside of the housing 510. The piezoelectric member 530 may be made of any piezoelectric material, including, but not limited to, one or more of: (i) quartz, (ii) lithium niobate, (iii) langasite, and (iv) GaPO₄. The piezoelectric material may be selected based on the intended operating environment. The piezoelectric member 530 may be covered by a conductive layer 550. Conductive layer 550 may be grounded or biased through an electrical connection 540 with the housing 510. The member 530 may be located within housing 510 such that it is surrounded by fluid 220. A pair of electrodes 560 may be located on the inside of the housing 510 and radially concentric with the piezoelectric member 530. The electrodes 560 may include an insulating layer 565 to protect the electrodes from contact with fluid 220. One or more of the connection points 540 may be operably connected to a sensor 580 configured to measure changes in the movement of the piezoelectric member 530. In operation, a power source (not shown) may energize the electrodes 560 to induce vibrations in the piezoelectric member 530. The motion of the piezoelectric member 530 may generate a shear wave in the fluid 220. Viscous damping of the fluid 220 on the surface of the piezoelectric member 530 may be detected in the time domain by observing the freely decaying torsional oscillation of the piezoelectric member 530 or in the frequency domain by using a sensor 580. The rate of damping of the shear waves in the fluid 220 may be used to characterize properties of the fluid 220. The damping of the shear waves may be estimated from the change in motion of the piezoelectric member 530 as the fluid 220 resists the vibratory motion of the piezoelectric member 530. The change in motion of piezoelectric member 530 may be estimated at sensor 580. The amount and/or rate of change in the motion of piezoelectric member 530 may be used to determine rheological properties of the fluid 220.

FIG. 6 shows another embodiment of the analyzer 500 using a piezoelectric member 530 that is inserted into the fluid 220 such that the fluid flows across the piezoelectric member 530 rather than along its length (FIG. 5). The electrodes 560 may be mounted outside the housing 510 and may be isolated from fluid 220 by an insulator 665. Piezoelectric member 530 may be partially embedded in insulator 665. The portion of piezoelectric member 530 that is not embedded in insulator 665 may have a conductive layer 550 to isolate the piezoelectric member 530 from fluid 220. Insulator 665 may be configured to receive a sensor 580 that may be operably coupled to piezoelectric member 530 and may estimate the impedance of the piezoelectric member 530. In some embodiments, sensor 580 is responsive to the motion of the piezoelectric member 530. In some embodiments, a protective screen or sieve 690 may surround the piezoelectric member 530 to reduce damage to due particles in the fluid 220.

FIG. 7 shows an exemplary method 700 according to one embodiment of the present disclosure. In method 700, a fluid analyzer 200 may be positioned within a borehole 12 in step 710. In some embodiments, the fluid analyzer 200 may be configured to permanently reside downhole. Then, in step 720, fluid 220 may be moved into the fluid analyzer 200 from the borehole 12 or a sampling device 110. In step 730, which is optional, the fluid 220 may pass a magnetic catcher 290 (present in some embodiments) configured to reduce the amount of magnetic particles within fluid 220. In step 740, magnetic field source 260 may be energized to apply a pulsed magnetic field to the member 230, which may cause the member 230 to vibrate in at least one mode. The fluid 220 that has been moved into fluid analyzer 200 may be stationary or flowing when the magnetic field source 260 is energized. The use of a magnetic field source to apply a magnetic field to the member is exemplary, as other energy sources may be used to apply energy to the member. In some embodiments, the at least one mode of vibration may be one of: (i) torsional, (ii) lateral, and (iii) torsional and lateral. In some embodiments, instead of magnetic field source 260, electrodes 560 may be energized to cause piezoelectric member 530 to vibrate. In step 750, a sensor 280, 380 responsive to mechanical motion or magnetic fluctuations due to the vibration of the member 230 generates information indicative of the motion and sends the information to at least one processor. In step 760, at least one processor estimates the amount of damping caused by fluid 220 based on the signal from the sensor 280, 380. In some embodiments, step 750 may, instead or in addition to, involve estimating the energy consumed by the magnetic field source 260 applying the magnetic field to the member 230.

FIG. 8 shows a flow chart of exemplary method 800 according one embodiment to the present disclosure. In step 810, member 530 of fluid analyzer 500 may be immersed in fluid 220. In some embodiments, fluid analyzer 500 may be located in a borehole 12. In step 820, an electric signal may be applied to member 530 causing the member 530 to vibrate in at least one mode. In step 830, sensor 580 may generate information of damping of the motion of member 530 due to fluid 220. In step 840, at least one processor estimates the amount at least one parameter of interest based on the information from the sensor 580.

While the foregoing disclosure is directed to the one mode embodiments of the disclosure, various modifications will be apparent to those skilled in the art. It is intended that all variations be embraced by the foregoing disclosure. 

1. An apparatus for estimating at least one parameter of interest relating to a fluid, comprising: a member in the fluid, the member being responsive to an applied energy field, wherein the response includes at least one mode of vibration.
 2. The apparatus of claim 1, further comprising: a sensor configured to generate information representative of a damping of a response of the member.
 3. The apparatus of claim 2, wherein the damping is substantially caused by a liquid.
 4. The apparatus of claim 2, wherein the sensor is responsive to one of: (i) a mechanical force, (ii) a magnetic flux, (iii) electromagnetic radiation, (iv) differential heating, and (v) electrostatic force.
 5. The apparatus of claim 2, further comprising an energy source configured to generate the applied energy field, wherein the information relates to an amount of energy consumed by the generator.
 6. The apparatus of claim 1, wherein the at least one mode of vibration includes at least one of: (i) torsional vibration and (ii) lateral vibration.
 7. The apparatus of claim 1, further comprising an electromagnet configured to supply the applied energy field.
 8. The apparatus of claim 1, further comprising: a catcher positioned along a flow path of the fluid, the catcher configured to reduce an amount of magnetic particles in the fluid.
 9. The apparatus of claim 1, wherein the member is formed at least in part of a material that generates a magnetic field.
 10. The apparatus of claim 9, further comprising: a sensor configured to generate information representative of the magnetic field generated by the member.
 11. The apparatus of claim 9, wherein the applied energy field and the generated magnetic field interact to induce a motion of the member.
 12. The apparatus of claim 1, wherein the member is configured to generate eddy currents in response to the applied energy field.
 13. The apparatus of claim 1, wherein the member is formed at least in part of at least one of: (i) a piezoelectric material and (ii) a metal.
 14. The apparatus of claim 1, further comprising an energy source, wherein the energy source is configured to generate the applied energy field.
 15. The apparatus of claim 14, wherein the energy source includes an electric field generator in electrical communication with the member.
 16. The apparatus of claim 1, wherein the member is configured to cause shear waves in the fluid in response to the applied energy field.
 17. A method for estimating at least one parameter of interest relating to a fluid, comprising: estimating the at least one parameter of interest using information representative of a damping of at least one mode of vibration of a member in the fluid, the motion being caused by an applied energy field.
 18. The method of claim 17, further comprising: applying the energy field to the member.
 19. The method of claim 17, further comprising: generating shear waves in the fluid using the member.
 20. The method of claim 17, further comprising: generating the information using a sensor. 